Asking about GDM

Hi moms, I’m currently 30 weeks pregnant. Last week, I had a baby scan, and the doctor mentioned that my baby's tummy is slightly bigger than the head. I had pre-diabetes before pregnancy, which has led to gestational diabetes (GDM) during pregnancy. Besides exercising and controlling my diet, what else can I do? Has anyone else experienced this? Could you share your experiences? Did you have a natural birth or a C-section?